Autism, or autism spectrum disorder (ASD), refers not only to a single disease but to a wide range of conditions. Autistic people may present challenges with social, communication and behavioural skills. Whilst ASD can be very different for each person, there are some common characteristics that we can identify at different stages in life. In this article, we’ll define ASD and review the common characteristics of this group of conditions.
We are used to identifying autistic people by the fact that they act differently from others starting at an early age, exhibiting a difficulty to communicate with their peers or perhaps finding it hard to understand how others feel. However, it is important to understand that autism is a much more complex manifestation of how the brain works.
Autism spectrum disorder refers to a complex neurodevelopmental disorder that impacts how a person perceives and relates to others, which can lead to problems in social interaction and communication.
It is important to note that each affected person shows specific signs with varying degrees of severity, therefore going through very different challenges and developing specific abilities. Consequently, the way in which people affected by ASD think, learn or solve problems can vary from relative ease to a severe challenge in some cases. Some people with ASD show above average intelligence, while others show learning difficulties.
In ASD genetic and non-genetic factors interact in the development of the condition. Characteristics of autism sometimes also includes sensory sensitivity and medical problems such as gastrointestinal disorders, sleep disorders, seizures, as well as mental health problems such as anxiety, depression, or attention difficulties. There are other conditions like Asperger or non-specific pervasive invasive developmental disorder that have been reclassified under the ASD umbrella.
Despite the fact that each child with ASD is different from the others, and that the age of onset varies, it typically appears in the first 3 years of life. There are a series of warning signs that may make a comprehensive assessment of development recommendable. These are shown below, highlighting that the signs established in the previous stages can be present at any age. Of course, not all the children that presents any of these signs will be diagnosed with autism, the list below is just a guidance to have further specialized evaluation.
Between 12 and 18 months of age:
Around 24 months of age:
As they get older, children with ASD may develop some other tell-tale signs:
At the moment, it is not possible to determine a single cause that explains the development of ASD, apart from the strong genetic implication in its origin. The estimated prevalence of ASD is about 1%-2%, being 2-3 times more frequent in males than in females.
Autism may result from disruption of normal brain foetal development early in stages, caused by defects in genes that control brain growth and regulate how neurons communicate with each other. Genetic causes including gene defects and chromosomal abnormalities have been found in 10-20% of affected individuals. In case of siblings born in families with ASD, they have a 50-times higher risk of ASD, with a recurrence rate of 5-8%.
In some cases, ASD can be associated with a genetic disorder already present, such as fragile X syndrome, meningitis infection, congenital rubella, phenylketonuria, or tuberous sclerosis.
One crucial point to retain is that autism is not caused by childhood vaccines. There have been no correlations found in extensive studies around the occurrence of ASD and vaccinations.
Once a person who exhibits the characteristics of autism has been correctly diagnosed, there is no actual “cure” and treatment will vary depending on each personal case. There are various therapies that can be deployed early in a child’s life and they are more effective the sooner they are implemented.
The goal of ASD therapies is to maximize the ability of affected individuals to function, develop and learn.
Most people with ASD respond good to a highly structured and organized life. In some cases, these measures can help reduce symptoms and provide people with autism tools to accomplish their daily activities.
Persons affected by autism usually exhibit symptoms as early as 2-3 years of age. For some cases, some developmental delays appear earlier and can be observed and diagnosed as early as 18 months of age.
However, because of the very personal and diverse nature of the symptoms ASD can entail, it can sometimes be difficult to diagnose the disorder and to determine its severity. Normally, a child’s doctor will check for signs of developmental delays as part of regular check-ups, and they will ask for a specialist to be consulted if any findings are detected.
When meeting with a specialist, there is unfortunately no specific medical test that can be done for an autism diagnosis. Instead, a specialist will try to observe the child and find out more about the nature of their social interactions, the level of their communication skills and how their behaviour have developed, as well as stablish the hearing, speech and language developmental levels.
Genetic testing can also be used to diagnose ASD. As we have mentioned above, genetic factors are associated with the development of autism. Several genes have been identified and are involved in the regulation of gene expression and in neuronal communication. Next Generation Sequencing (NGS) technology has shown to provide a higher diagnostic yield than other molecular approaches and, thanks to the technological advances together with the decrease in the sequencing costs, whole genome and exome sequencing are being positioning as first-tier tests in the genetic diagnosis of ASD.
Veritas offers genetic counselling for the patients and different diagnostic genetics options, including whole genome or exome sequencing with expert interpretation. Please contact us for more information about this service.
Maria Moreno - Medical Science Liaison Manager
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